The two factors of a quadratic equation can be multiplied to form the original equation. Let the missing term be a: y² + 15y + 56 = (y + 7)(y + a) y² + 15y + 56 = y² + (7 + a)y + 7a We can now compare the coefficient of the like terms, either the one with y or the one without y, and find the value of a. 15 = 7 + a; a = 8 OR 56 = 7a; a = 8